Rubber derivatives products



Patented Dec. 5,

un -Tao sTAresY PATENT} OFFICE RUBBER DERIVATIVES PRODUCTS James A.Mitchell, Kenmore, N. Y., assignor to E. I. du Pont de Nemon'rs aCompany, Wil- -mington, Del., a corporation of Delaware I No Drawing.Applic ation September 16, 1941,

I sci-n1 No. 411,039

IOClaims. (CI.L 80'768) This invention relates to moisture resistantsheetv wrapping material, especially transparent,

moistureprooi'ed, non-fibrous sheet. More partlcularly it-appertains' tonon-tacky, heat-sealable, age-resistant moistureprooflng coatings onillms of regenerated cellulose and the like.

One of the newer sheet wrapping materials. consists of a thin,cellulosic base sheet having a material (material which does notdissolvemore 7 than an infinitesimal amount of, if any water), for example, awaxysubstance such as paraffin wax, a cementing (binding, film-forming)material therefor, for example, cellulose nitrate. Generally the basefilm contains softening material, for example, glycerol, and the coatingcontains plasticizing material, for example, dibutyl phthalate, topromote flexibility.

To overcome any haziness which might result from some proportions andcombinations of other a I components of the coating, transparentizing(blending, homogenizing) material, for example, resins and gums such asdamar and ester gum, is ordinarily included.

When rubber is worked on a rubber mill (or.

related apparatus, such as a Banbury mixer) with about to-55% its weightof beta-naphthol (or similar monohydric phenol) in the presence of asmall amount of a special catalyst, for example, di-hydroxy-fluoroboricacid or sulfuric acid, for about minutes at 100 C., a material (forconvenience called Phenol rubber product 2,158,530, or more simply,"phenol rubber product") is obtained which is quite unlike rubber andthe heretofore known rubber derivatives (including the products known asrubber isomers). The new material, being denser, sinks whenplaced inwater, will not adhere to rubber, is more soluble in hydrocarbonsolvents than cyclized I rubber (J.-I. E. C. XXXIH, 389), and whenmixedwith rubber on a mill and the mixture made into a thin cement,layers oil. The material seems to be an alkylated phenol (rubber beingthe alkylating agent), since the phenol-molecule seems to havechemically combined with the rubber molecule (probably at what was. anunsaturated carbon atom in ordinary rubber), the reaction productaccording to- U. s. P, 2,158,530 containa ing 1 to 5% of chemicallycombined phenol.

Surprisingly, it has now been foundjthat this material can be reactedwith maleic :anhiniride" and related carbonyl compounds containing oryielding derivatives containing the grouping COC=C- (for example,itaconic acid and citric acid), The resulting resinous materials can beused very satisfactorily in the preparation of moistureproofingcoatings.

' It was an object of this invention to provide improved coatingcompositions. Other objects were to produce improvedmoistureprooflngicoating compositions, improved moistureproofing'coatings and improved moistureproofsheetwrapping material. Furtherobjects were to produce improved ,moisture resistant, non-fibrous,pellicles, to produce satisfactory coating compositions comprisingphenol-rubber-product derivatives, to produce coating compositions whichwould adhere flrmly to a flexible base sheet even when subjected tomoisture and/or water for long periods of time, to producephenol-rubber-product derivative compositions which would be stable overlong periods of time, to produce coating compositions exhibiting highstability, to produce moisture-resistant coating compositions comprisingphenol-rubber-product derivatives, moistureprooflng agents andconventional constituents,-

to provide transparent, non-fibrous, moistureproof, regeneratedcellulose and like sheet wrap ping materials comprising stable phenolrubberproduct derivative compositions, to produce coating compositionswhich give adhesive bonds of strength satisfactory for laminating thin,flexible,

non-fibrous sheet materials, to produce coating compositions which wouldremain stable when exposed to high temperatures, heat, andthe like forlong periods of time, and to produce coating compositions which wouldgive adhesive bonds of good strength on the application of heat andpressure. A general advance in the art, and other objects which willappear hereinafter, are also contemplated. v

It has now been found that compositions prepared from carbonyl compoundderivatives from phenol-rubber products, for example, moistureproofingcoatings, have excellent heat scalability,

a unless otherwisespecifled;

give adhesive bonds which are initially very good and remain so for longperiodsof time, and are; stable and transparent after long exposure tolight,- high temperatures, etc.

How the foregoing objects and related ends are accomplished will beapparent from the following exposition, in which are disclosed theprinciple and divers embodiments of the invention, including the bestmode contemplated ior'carry given by weight ing out the same. Harts areeralweeks exposure at 95 F. (35 C.). I have a permeability value of 10,a heat sealing Example I Prepare a 450 gauge web or regeneratedcellulose in the manner described in U. S. A. Patent No. 1,548,864(Brandenberger), that is, by casting viscose, coagulating, regenerating,desulfurins. bleaching, washing free from impurities, softening anddrying. Use an aqueous bath containing 4.33% glycerol for softening, userollers heated to 60-90 C. for drying, and bring th dried sheet tonormal humidity.

Heat a solution of: a

I Parts Beta-naphthol-rubber product (purifled 25.0 Cinnamic acid 3.0Benzoyl peroxide. 0.25

Toluene Excess (unreacted) beta-naphthol removed, under a refluxcondenser at approximately 115' C. for five hours,

839 Ctnen incorporate 2.5 parts of paraflln wax (M. P.

Coat the regenerated cellulose web with the resulting composition. Carryout the coating of theweb by passing it continuously through a bath oithe aforementioned solution maintained at 35 ,C. Remove the excesscoating material by scraping with doctor knives. and dry the coated web(remove the volatile solvent) at a tem- 'perature slightly above themelting point of the wax.

Employ enough oi the moistureprooflng coating composition so that thefinal product will have an amount proportional to two pounds for each3.000 suuare feet of web surface (this quantitynto include the coatingon both sides of the we 1 Parts Beta-naphthol-rubber product (purified)-25.0 Citraconic anhydride 2.0

Benzoyl peroxide 0.25 I. Toluene- 225.0

at 115 C. for 4 hours under a reflux condenser. Coat regeneratedcellulose web with this composition in the manner described in ExampleI.

The coating will show no loss in adhesion and heat sealingcharacteristics after several weeks exposure at 95 F. (35 C.). It willbe transparent, moistureproof, flexible, and have a permeability valueof 10 and a heat seal value of 150.

Example IV Prepare a moistureprooflng coating composition by dissolving2.5 parts of paraflln wax (M. P.

C.) in a solution prepared by heating:

' Parts Beta-naphthol-rubberproduct (purifledL 25.3

Crotonic acid Benzoyl peroxide Toluene 225.0-

at 115 C. for 4 hours under a reflux condenser.

Coat regenerated cellulose web with this composition in the mannerdescribed in Example I.

The coating will show no loss in adhesion and heat sealingcharacteristics after several weeks exposure at F. (35 C.) It will betransparent, moistureproof, flexible, and have a permeability value of10 and a heat seal value oi'140.

Example V 7 Prepare a coating composition by heating un- V der refluxingconditions for 5 hours at '-115 C. a solution consisting of:

Y The result ng product will be moistureprooi' (have a permeabilityvalue of 25). heat scalable (have a heat sealing value of 240),,trnsparent, flex ble, colorless, and quite non-tacky. The

coating will show no loss in adhesion and heat seal ng characteristicsafter several posure at 95 F. (35 C.).

A product prepared in exactly the same manher. but omittingthe refluxingstep in the preoweeks' exarat on of the moistureprooflna'coatingcomposition, will lose its adhesion (if sealed) r heat under refluxingconditionsat'about C. for 4 hours, and then adding 2.5 parts of paraflinwax (M. P. 60 0.). Coat regenerated cellulose web with this compositionin the manner described in :Example I. The coating will show no loss inad Parts Beta-naphthol-rubber product (purified) 20.0 Maleic 'anhydride1.0 Benzoyl peroxide 0.2 Toluene 180.0 Paraflin wax (M. P. 60. C.) 2.0

Coat regenerated cellulose web with this oomposition in the mannerdescribed in Example I. It will have a permeability value of 10, a heatsealing value of 800, and be transparent and flexible. .A loss inadhesion and heat sealing properties will be considerably less than thatin a product obtained in an identical manner but omitting the heatingunder reflux, in other words, the reaction between the unsaturated acidmaterial and the beta-naphthol-rubber product V gives a product whichretains its original characteristics much longer than would a mixture ofthe ,unreacted products.

hesion and heat sealing characteristics after sev- It will 'value of200, and be transparent and flexible.

Example III.

Prepare a moistureprooflng coating composition by dissolving 2.5 partsof paraflin wax (M. P.

60 C.) in a solution prepared by heating:

. Example VI Heat a mixture of:

Beta-naphthol-rubber product (pained) 20.0 Maleic anhydride 'Lauroylperoxide -a Toluene i 180.0 Paraflin wax (M. P. 60 C.) 2.0

at 110-115 C. for six hours and coat regenerated. cellulose web with theresulting solution in the manner described in Example I. The resultinproduct will be moistureproof. (have a permeability value of 8),. andhave good heat sealina properties (heat seal value 1 25). It will showno degradation inheat scaling properties and adhesion after two weeksfree exposure at 95 F.

I (35 C.) v

Parts 0531'.- (35 0.). It will have a of 'l'and a heat seal value of130.

If'jthe heating is omitted, the resultina product win showpraetiesncomplete loss or heat sealing properties and adhesion to the base sheetin less than one week. As will be apparent from e a comparison with theproces in which heating is employeda chemical reaction takes place be,-

tween the beta-naphthol rubber product and the malelc anhydride onheating at ll-ll5 C.

I Example wt Heat a mixture of Parts BetaenaphthoI-rubber product(purified) 20.0 Maleic 'anhydride 2.0 Benzoyl peroxide 0.1. Toluene180.0 Paramn wax (M. F. 60 C.) 2.0

at 1,10 -.120 C. for four hours,'and coatjegenerated cellulose web withthe resulting solution in the'manner described in Example I. Theresulti'ngproduct will retain its adhesion and heat sealinggpropertiesatterrour weeks",'exposure,at

permeability yalue Example Vlll Heat a mixture 01':

at '1 10-120 c. for four hours, and coat regenerate'dcellulose web withthe resulting solution in I the manner described-in Example I. Theresultin; product willretain its adhesion and heat sealingflpropertiesafter three weeksexposure at 35 C. It will have a' permeability value ofand a at film-.120 (Liar four hours, and coat regenerated cellulose webwith the resulting solution in ,the manner describedin Example I. re-

sulting product will retain its adhesion and heat sealingproperties'alter three weeksie no r 1a 351 c. It will havefapermeability value or '10 and aheat seal value of 110.

' mane x Heat a ot Reg stries-m r product segment-- '20s.

.. Parts 2 Parts Beta-haphthol-rubber product (purified) l- 20.0 Malei-canhydride 2.0 Toluene 180.0

Paramn wax (M. P. 60 C.) 2.0

erated cellulose film with the resulting solution in the mannerdescribed in Example I. The resulting product will retain good adhesion,moistureprooiness, anchorage and heat sealing properties afterthreeweeks" exposure at C. It will have a permeability value of 5 and aheat seal value of 160.

Example XII V Reflux a solution of:

V Parts- Beta-naphthol-rubber product (purified)-.. 40.0 Maleicanhydride 2.0 Benz'oyl peroxide 0.4 Toluene 200.0

for five hours at a temperature of ll0 115 C., and isolate the resultingsolid product. The isolation may be accomplished in various ways, for

example, by evaporating oi! the solvents under vacuum or byprecipitatinz'by the toluene solution into alcohol with gstirring,followed by washing with water and drying.

ing is applied to paper,'lacquer coated paper, 7

The resulting product, when dissolved in a suit able solvent such astoluene, benzene or naphtha.

and coated on regenerated cellulose sheet, will show good adhesion andheat sealing P QDertles, and retain these properties for -a considerablylonger time than coatings of thesame beta-naphthol-rubber productunmodified by treatment with maleic anhydride and similarly coated fromasolutlon. w v y Similar properties are obtained when thecoatwood,lacquer coated wood, lacquer coated metal, and cellulose acetate. Suchcoatings will be of the moistureprooi' type if wax is dissolved in thesolution before it is used for coating.

heat seal value of 130.

1 Example IX Heat a mixture oi:

a z Parts Betaenaphthol-rubber product (purified) 20.0 Maleic anhydride2.0 Paratoluene sulfonic acid 0.4 Toluene 180.0 Paraffin wax (M. P. C.)2.0.'

Beta-naphthol-rubber product (purified) 20.0 Maleic anhydride 1.0.Benzoyl peroxide 0.2

, Toluene 180.0 Hydrogenated'methyl abijetates 2.0 Paraffin wax '(M. P.60 C.)'-- 2.0

at 51 10 120" 0. for four hours; organic solvent soluble celluloseacetate. sheet wrapping material with the resulting solution in the man''ner desfcrilxsd in Examplel. .Theresultlng prod-.

uct'wil'l retain its adhesion and-heat sealing properties' after threeweeks exposure at 35 0. It

have" a permeability value of 8 and a heat ,sealvalue of 145. p

7 Heat amixture of:

Example x111 Heat a mixture of:

at -12o" c. for mmhoursgandljcoat time solvent soluble celluloseacetate; sheet wrapping material with the resulting solution in.themener de cribed in Example 1., The resulting prod uctwill retain itsadhesion and heat sea-ling brow erties. after three weeks" expogpre at}?(2. It will have a permeability value of 8 and a heat seal'valueoi145.

Example Beta-naphthol-rubber product'lpurifled); 25.0.

under a reflux condenser at approximately 1-l5' C. for hours and thenincorporate in the re- 1 sultant 2.5 parts of paraffin wax (M. P. 60'C.), and coat regenerated cellulose film with the resulting solution inthe manner described in Example I. The resulting product will bemoistureproof, heat scalable, transparent, flexible, nontacky,colorless, and have good slip, a permeability value of 25 and a heatsealing value of 240.

Example XV Prepare a moistureproofing coating composition' by dissolving2.5 parts of paraflin wax (M. P. 60 C.) and 2 parts of ester gum, in asolution prepared by heating:

. Parts Beta-naphthol-rubber product (purified)- 25.0 Citraconicanhydride 2.0 Benzoyl per 0.25 Toluene 225.0

at 115 C. for 4 hours under a reflux condenser.

Coat regenerated cellulose web with this composition in the mannerdescribed in Example I.-

The coating will show no loss in adhesion and heat sealingcharacteristics after several weeks exposure at 95 F. (35 C.). It willbe transparent, moistureproof, flexible, and have a permeability valueof and a heat seal value of 150.

Example XVI Prepare a moistureprooflng coating composition by dissolving2.5 parts of paraffln wax (M. P. 60 C.) and 2 parts of coumarone-indeneresin in a solution prepared by heating: 1

' Parts Beta-naphthol-rubber product (purifled) 25.0 Crotonic acid 3.0Benzoyl permririe 0.25 Toluene 225.0

Example XVII Use a composition consistina of:

Beta-naphthol-rubber product (purified)- maleic acid product (of Ex.XII) Polyb'uten'e (molecular wt. 7,000) 30 Paraflin wax (M. P. 60 C.) 25Toluene 100 1.1. n. c. xxxu 299, 131.

to adhere two sheets of plain, transparent, regenerated cellulose film.The laminated product will be transparent and moistureproof.

Example XVIII a'composition consisting 0!:

Parts Beta naphthoi-rubber product (purified)- maleic acid product (ofEx. x11) 50 Hydrogenated methyl abietate 30 Paraflin wax (M. P. 60 C.)20

to adhere two sheets of plain, transparent, regenerated cellulose fllm.The laminated product will be transparent and moistureprool.

The phenol rubber product-unsaturated car- Parts boxylic acidcondensation (reaction) product is new. In its preparation,phenol-rubber products from various phenols may be employed. One or morephenols may be used in preparing the phenon-rubber product, and one ormore phenolrubber products may be used in the maleic anhydride typecondensation.

The carbonyl compounds condensed with the phenol-rubber products arehydrocarbon carboxylic acids and anhydrides. The carbonyl group may beattached to saturated or unsaturated carbon atoms, that is to say,carbonyl compounds may be aliphatic, alicyclic or aryl. They may bemonoor polybasic. The preferred acids are acrylic, crotonic,methacrylic, .cinnamic, maleic and itaconic. The correspondingacidanhydrides. as just indicated, can also be used, for example, maleicanhydride, citraconic anhydride. etc. Compounds decomposing to theseacids and their anhydrides as a result of the heating which I takesplace during the reaction, for example malic acid (yielding maleicacid), citric acid (yielding itaconic acid and citraconic acidanhydride), etc., can also be used, and being equivalents, areconsidered within the scope of this invention and the terminology usedto describe it. I

The condensation is preferably "carried out in a solvent. Variousorganic liquids such is aromatic' hydrocarbons (benzene, toluene,xylene, etc), naphtha solvents and chlorinated hydrocarbons, aresuitable. In the absence of solvents, suitable mixtures of theingredients may be employed. The reaction may be carried out undervarious conditions of temperature and heating at 110 C. A product heatedfor only 2 hours at 100-1'10 C. can be used to advantage. Naturally thetime of reaction varies with the temperature and the efllciency of thecatalyst] Catalysts other than those mentioned inthe speciflc examples,for example, hydrogen peroxide,-

may be employed, or if the particular circumstances involved do notinterfere with a relatively longer reaction period, the condensationmaybe carried out in the absence of a catalyst. No advantage has beenfound in using more than 15% maleic anhydride (or equivalent quantitlesof other carbonyl compounds) based on the combined weight of thereactants.- There are economic disadvantages in using more than thisamount, since the additional material does not seem to produce anydifference in the final product. A definite improvement results withquantities as low as 0.1% maleic anhydride, so these figures may betaken as the maxima. and

, minima of the preferred range of proportions.

The phenol rubber products (used for the re action with the unsaturatedcarbonyl'compound) are resinous, transparent, thermoplastic,benzene-soluble derivatives of'mibber which, are resistant to acids andalkalies, which do not adhere to rubber, which have an impact strengthsimilar to phenol aldehyde resins, which impart a hardness to rubber(when compounded therewith) like glue and Montan wax, and which areobtained by reacting rubber with a monohydric phenol which contains nosubstituents other than halogen and hydrocarbon radicals. The phenolrubber products can be hydrogenated at temperatures in the range 80- C.in the presence of an acidic catalyst. The preparation of the phenolrubber product is described in U. S. A. Patent No. 2,158,530 (Williams),and reference is made thereto for details. For convenience it may bepointed out that the amount of the phenolic material (phenol, naphthol,etc.) may vary widely, the ordlnarylimits being to 55% (based on therubber). The products prepared by milling 5 to 20 parts of beta-naphtholwith 100 parts of rubber-in the presence of 4 parts of sulfuric acid asa catalyst, are the preferred starting.

materials. Although this type of material (using 10 parts ofbeta-naphthol) was employed in the specific examples, it is to beunderstood that any one or a plurality of the type of products disclosedby the patent just mentioned may be employed, when desired. I

The crude phenol-rubber product (containing excess phenolic material)may be used, but the best results have been obtained when the excess 1of the phenol was removed. Ordinary extraction procedures utilizing suchmaterials as alcohol solvents, such as ethanol and butanol, are suitablefor removing the unreacted phenolic material. The reaction product mayalso be purified by dissolving in toluene and precipitating the phenolrubber product with ethyl alcohol (which retains the phenolic body insolution). Treatment of the crude reaction product with formaldehyderenders the excess phenolic material innocuous .-by causing it to form aphenol formaldehyde resin, whose presence in the composition is notordinarily. objectionable (because it does not exude or blush out as thefree phenolic compound would).

Various phenols in addition to the hydroxyganic sulionic acids,hydroxy-fluorboric acid and boron trlrluoride, may be employed.

The phenol-rubber products of this invention may be designated by avariety of names other than those already mentioned, for example, rubber alkylated phenol," phenol modined rubber," rubber substitutedphenol," and phenol rubber condensation product. These terms, as used inthis application, are intended to apply only to the type of materialobtained according to the aforementioned U. B. A. Patent No. 2,158,530.They are not to be construed broadly enough to cover isomers or likederivatives of rubber which might be obtained by using phenol orphenolsulfonic acid in a simple catalytic capacity. a

As the moistureprooflng agent, any wax (used generically, to includewaxylor wax-like) sub stances like parafllnwax, as well as true waxeswhich are monohydric alcohol esters of higher *fatty acids) or mixtureof waxes, maybe employed. Ordinarily paramn wax melting above 50 C.,'orbetter, that melting at 60 C. (and above), is preferred.

The incorporation of wax in compositions con- "taining the newphenol-rubber product deriv- Noticeable improvement is obtainable witheven smaller amounts. The wax may be'added either before or after thephenol-rubber product is reacted with the carbonyl compound.

The properties of the new phenol-rubber-prod uct derivative compositionsmay be enhanced and modified in known ways, by the incorporation ofminor proportions of othermaterials. Details of the conventionalmodifying practices such as dyeing, pigmenting, plasticizing (orsoftening),

transparentizing, and like procedures and materials used therein, arewell known and are disclosed in the patents listed elsewhere herein.Reference is made thereto for specific details. Beneficial results arefrequently brought about by incorporating natural and/or syntheticresins.

Organic solvent soluble amino polymers (basic amino nitrogen-containingpolymers) of thetype disclosed in U. S. A. Patent No. 2,190,776(Ellingboe & Salzberg) may be added to the composition for further orspecialized protection. These materials are also soluble in 2% aqueousacetic acid, Anti-oxidants and other stabilizers may be added for thesame purpose. r

In preparing the coating compositions, any solvent dissolving thephenol-rubber product-unsaturated carbonyl compound condensationproduct, may be used, althoughhydrocarbon solvents, particularlyaromatics such as benzene, toluene and xylene, are prei'erred. Mixedsolvents such as thosecontaining minor proportions of keilones, esters,or alcohols, may be used. These compositions may be appliedlas melts athigh tem Pera-.

'tures, in which case no solvent, or only a minor proportion or solvent,need be present.

The new phenol-rubber product-unsaturated carbonyl compound reactionproducts are especially useful in coating compositions applied totransparent, smooth, substantially non-porous, non-fibrous sheet, suchas those composed of cellulosic material, for example, regeneratedcellulose and cellulose acetate, albuminous' material, for example,gelatine and casein, and polyvinyl compounds, ior example, polyvinylalcohols and polyvinyl Water sensitive sheet obtained by coagulation orprecipitation and/or regeneration ,from aqueous (or aqueous alkaline,

tor example, alkali metal hydroxide and the like) dispersions (orsolutions), for example. viscose, cuprammonium and like regeneratedcellulose, polyvinyl alcohol, low (lowly) substituted (less than one moiper glucose unit) cellulose ethers (U, S. A. Patent No. 2,123,880 toEllsworth), such as glycol cellulose, cellulose glycolic acid, alkyl(methyl, ethyl, etc.) cellulose, and the like, are especiallysatisfactorily coated with the moistureprooiing compositions of thisinvention. As indicated above, the presence of the new phenol-rubberproduct derivatives also improves coating compositions used on organicsolvent soluble compounds like cellulose ethers, for example, ethylcellulose, and cellulose esters, for example, cellulose acetate. Thesame is true with paper. modified paper, lowly esterifled cellulose,etc. The new compounds can also be used to coat labrics, to preparemolding materials, to act as cementing (binding) agents in protectivecoatings for wood, metal, etc, as adhesives, and tor nuv moistureproorsheet, wrabillng mat ings, etc.

By the expression ancho'r" or equivalents (anchoring, anchored, etc.) ismeant the securing of the surface coating on the. base in such a waythat the resulting product will withstand the deleterious efiects ofwater (or moisture). Whether a substance is an anchoring agent or not iseasily determined, for example, by comparing the time of immersion inwater required to loosen a moistureproofing coating containing 1 thesubstance, with the time required to bring about the same loosening withthe coating omitting the substance being tested (but otherwise havingthe same proportions of ingredients). Compositions of this invention,when tested by immersion in water at 20 0., give a several-foldimprovement in the time required to loosen the coating from the watersensitive and non-moistureproof base sheet.

Moistureproofness, moistureproofing' and moistureproof materials andexpressions are defined I in U. S. A. Patent No. 2,147,180.(Ubben) Inthe interest of brevity the definitions are not repeated here. The termsand expressions related thereto and employed herein are used inaccordance with such definitions.

Heat seal bond and heat seal bond strength are defined and a standardtest for their determination is given in U. S. A. Patent No. 2,147,180(Ubben). In the interest of brevity the definitions and test descriptionare not repeated here. The terms and expressions related thereto andemployed herein are used in accordance with such definitions anddescription.

The phenol-rubber product-carbonyl com-' pound derivatives are morestable by far than the phenol-rubber products from which they are made.It i therefore possible to produce moistureproofed products which retaintheir desirable properties over a much greater period of time 1 than hasbeen thought possible heretofore. This 1. A condensation productconsisting of phe nol-rubber product reacted with maleic anhydride, at atemperature of 60-150 C., said phenol-rubber product being a reactionproduct of rubber and a phenol containing 1% to 5% of the phenolchemically combined with the rubber.

2. A condensation product consisting of phenol-rubber product reactedwith a carbonyl C0111- pound from the group consisting of acrylic acid,crotonic acid, methacrylic acid, cinnamic acid, maleic acid, itaconicacid, maleic acid anhydride, citraconic acid anhydride and citric acid,at a temperature of 60-150 0., said phenol rubber product being areaction product of rubber and a phenol containing 1% to 5% of thephenol chemically combined with the rubber.

' 3. Sheet material coated with a condensation product consisting ofbeta-naphthol rubber product reacted with a carbonyl compound from thegroup consisting of acrylic acid, crotonic acid,

-methacrylic acid, cinnamic acid, 'maleic acid, itaconic acid, maleicacid anhydride, citraconic acid anhydride and citric acid, at atemperature of 60-150 C., said betanaphthol rubber product being areaction product of rubber and a betanaphthol containing 1% to 5% of thebeta-naphthol chemically combined with the rubber.

4. Regenerated cellulose coated with a condensation product consistingof phenol-rubber-,

condensation-product reacted with a carbon? compound from the groupconsisting of acrylic acid, crotonic acid, methacrylic acid, cinnamicacid, maleic acid, itaconicacid, maleic acid anhydride, citraconic acid'anhydride and citric acid, at a temperature of 60-l50 C., saidphenolrubber product being a reaction product of rubis particularly truewith regard to such characteristics as hardness, adhesion of the coatingto the base sheet, strength of adhesive bonds obtained by theapplication of heat and/or pressure,

' transparency, and general optical characteristics, absence of color,insensibility ,to water and moisture, lack of tackiness, etc. As aresult, the .moistureproof sheet wrapping material described above iswell adapted to be handled readily upon automatic wrappingmachinery,because the individual sheets do not stick to each other or the machinesurfaces with which they come in contact, and for the wrapping of wetproducts h ber and a phenol containing 1% to 5% of the phenol chemicallycombined with the rubber.

5. A moistureproofing coating composition comprising essentially 3%-l5%wax and a condensation product consisting of phenol-rubber productreacted with maleic anhydride, at a temperature of -'150 C., said phenol-rubber product being a reaction product of rubber and a phenolcontaining 1% to 5% of the phenol chemical ly combined with the rubber.6. A thin,'fiexible, sheet material comprising film of a moistureproofcomposition, saidmolstureproof composition comprising essentially 3%-15% wax and cementing material therefor, said cementing material being acondensation product consisting of phenol-rubber product reacted with acarbonyl compound from the group consisting of acrylic acid, crotonicacid, metha- 'crylic acid, cinnamic acid, maleic acid, ita'oonic acid,maleic acid anhydride, cltraconic acid-anhydride and citric acid, at atemperature of 1 60--150 C., said phenol-rubber product being a asbutter, fish, etc., even when exposed to light,

' heat, oxygen of the atmosphere, etc.

As many apparently widely diflerent embodiments of this invention may bemade without departing from the spirit and scope'thereof, it is to beunderstood that this invention is not limited to the specificembodiments thereof except as defined in the appended claims.

I claim:

reaction product of rubber and a phenol containing 1% to 5% of thephenol chemically combined with the rubber.

' '7. The process which comprises reacting the reaction product ofrubber and a phenol containing 1%-to 5% or the phenol chemicallycombined with the rubber. and a carbonyl compound from the groupconsisting of acrylic acid, crotonic acid, methacrylic acid, cinnamicacid, maleic acid, itaconic acid, maleic acid anhydride, citraconicacidanhydride, and citric acid. at a temperature of 60 to C. v

8. The process which comprises reacting the reaction productof'rubber'and a phenol containing 1% to 5% of the phenol chemically withthe rubber, and a carbonyl compound from the group consisting of acrylicacid, crotonic acid,

' ture of 60 in 150 C.

itaoonic acid, maleic acid anhydride, citraconic 7 acid anhydride, andcitric acid, at a temperature '0! 100 to 110 C.

9. The process which comprises reacting the reaction product of rubberand a phenol contain-' ing 1% to 5% of the phenol chemically combinedwith the rubber, and from about"0.1%. to about 15% by weight or maieicanhydride at a tempera 10." The process which comprises reacting thereaction product 0! rubber and a phenol containin: 1% to 5% of thephenol'chemicaily combined with the rubber, and from about 0.1% to aboutby weight 01' maleic-anhydride at a temperature 0! to C. v

- JAMES A. MITCHELL.

